Question

How many of the following have five radial nodes ? 
5s, 6s, 7s, 6p and 4p 

Answer 1

Correct Answer: 6

Calculation of Radial Nodes: 

The number of radial nodes for an electron in an orbital is given by:

Radial nodes = n - l - 1,

where:

• n: Principal quantum number
• l: Azimuthal quantum number

Calculations for the given orbitals:

• 5s: \(n - l - 1 = 5 - 0 - 1 = 4\) radial nodes
• 6s: \(n - l - 1 = 6 - 0 - 1 = 5\) radial nodes
• 7s: \(n - l - 1 = 7 - 0 - 1 = 6\) radial nodes
• 6p: \(n - l - 1 = 6 - 1 - 1 = 3\) radial nodes
• 4p: \(n - l - 1 = 4 - 1 - 1 = 1\) radial node

Conclusion:

Only the 6s orbital has five radial nodes. Therefore, the correct answer is 6s.